As regular readers will know, one of the records I keep of rehab horses is to film them on a level, hard surface and monitor how their landings change as their hooves become healthier. Most arrive landing toe first, some also have medio-lateral balance problems and these inevitably change as the foot becomes healthier.
I noticed that there has been a discussion over the last few days on the Horse and Hound forum about heel first landings, and one of the posters referred to our footage, which was nice (I know when we have been discussed on HandH because I suddenly have people visiting the blog from there(!)...). The discussion is here: http://www.horseandhound.co.uk/forums/showthread.php?t=408493 in full.
There is a combination of sensible, ignorant and frankly bizarre opinions on there, as is often the case (included in the latter is a comment by one Jaime Jackson trained trimmer who seems to think that its better for horses with tendon injuries NOT to land heel first and that a heel first landing is achieved by "invasive trimming"! Yikes!).
On a more constructive note, one poster commented on the fact that horses are filmed on level, hard ground and then asked "Are horses always supposed to land heel first?". Its a fair question, because it would be a biomechanical impossibility for a horse to land heel first in every scenario, and it seems that some people assume that, because its healthy for a horse to land heel first on hard, level ground, they should do so on all terrain and all surfaces. So, this post is designed to (I hope) clear up some misconceptions.
The reason I film horses where I do is because to film usefully you need to be able to see the landing, so it has to be on concrete rather than, say, in a school or field. That surface though is a test surface - rather as you would lunge a horse to check its soundness but don't expect your horse to spend all its time on a 10 metre circle.
Its healthy for a horse on a hard, level surface to land heel first - here is an example: http://www.vimeo.com/14334063. This isn't some human-imposed criteria, its a function of the horse's anatomy. The back (caudal) area of the hoof contains shock-absorbing structures, the toe doesn't. So for impact forces to be dissipated efficiently, a heel first landing is essential. The whole of the horse's limb anatomy is designed on this basis, which is why horses tend to develop soft tissue damage, particularly DDFT lesions, if they regularly land toe first on hard, level surfaces.
As I explain to students and owners, a heel first landing will be exaggerated as a horse walks down hill, so if you want to get your eye in for spotting it, having a horse walked down a gentle slope is useful.
Biomechanically, it makes complete sense - going downhill is concussive, so using the back of the hoof - in a healthy horse - minimises concussion. Pure gravity will also dictate that, as the ground falls away, the horse will naturally land heel first. By contrast, horses moving uphill will engage more toe first, partly down to basic mechanics, again - the ground rises up so the toe contacts the ground first. Equally, there is less concussion going uphill so less damage is done by a slightly toe first landing. In both cases, the steeper the slope, the more pronounced the change in landing.
So, simple biomechanics means that horses in the early stages of caudal hoof pain, navicular etc are reluctant to walk downhill - they are forced to engage the caudal hoof more than on the level, and it hurts. Horses like this will always prefer going uphill to going downhill, because uphill they can land toe-first, which is more comfortable for them. This is also the reason why wedged and bar shoes sometimes bring short-term pain relief for horses with caudal hoof pain.
When people say, however, that its normal for horses to land either heel or toe first, they are only partly correct. As with most things in life, it depends on context. Felix and Charlie will dig in with the toe first going up a steep hill, but on no other occasion. Racehorses at full speed on turf will land heel first - though many have weak caudal hooves and will tend to land flat or toe first on harder surfaces - thats not a healthy sign, though.
A horse landing toe first on a flat, level surface is, in my experience, a horse with caudal hoof pain and they are either already lame or heading that way. I am always happy when a rehab horse starts landing heel first, because its a sign that the caudal hoof is stronger. Equally, this post illustrates what happens over time to a "sound" horse with a toe first landing on level ground: http://rockleyfarm.blogspot.com/2009/11/toe-first-landing-what-happens-next.html
However, if you are watching your horse and it lands heel first on level ground but toe first going up a hill - don't worry, thats completely normal and perfectly healthy :-)